i can feel a bump when stopping and a bump when starting from a stand still start...

it only happens when i'm hauling an MT or load...doesn't do that when i'm bobtailing...

could it be the bushing on the fifth wheel???

 

any one :?:

 

Doesn't do it bobtailing due to no trailer.

How old is the fifth wheel?

If it's "wallered out" worn due to age and can't be repaired a new fifth wheel may be required...I'd have it looked at soon because it could quickly become a serious safety hazard.

 

[quote="HWD"]Doesn't do it bobtailing due to no trailer.

How old is the fifth wheel?


it's from a 2000 pete...

it doesn't do it all the time....

 

The adjustment of the 5th wheel could be off, the bushings could be shot could be a number of things.

Does it happen with the same trailer and not others or all trailers?

 

At best you probably need to adjust your 5th-wheel. At worst you need a rebuild or a new one.

 

Any truck garage will have a king pin on a handle to lock in the fifth wheel jaws and check for excess clearance. A mechanic can adjust the jaws. At a truck inspection site, you may be asked to rock the tractor with the trailer brake applied while they watch for movement of the upper fifth wheel plate on the fifth wheel.

 

Does it happen with the same trailer and not others or all trailers?[/quote]



seems to be with some trailers and with some it's okay...

it seems to be doing it more with the lower landing gear trailers when i try to hitch up...

sometimes when i back up easy it doesn't do it that much...

 

if you work for a company that has many older trailers or with a lot of drop and hook trailers the king pin can wear out quickly, if you are not sure you can take your truck to a good shop and they will have a test king pin and gauge tool to measure fifth wheel and king pins,your fifth wheel can be ajusted in most cases, if you are told it needs to be rebuilt DO NOT REBUILD it is safer to just replace the top plate about $500 to relace verses $275-300 to rebuild, all a rebuild does is replace the jaws the plate itself also wears. the more that it slops back and forth the more it will damage your fifth wheel.

 

Park the tractor-trailer, release the tractor spring brakes. With the trailer springs applied and the 5th wheel still fully locked... and then very cautiously, pull the tractor forward as if you were unpinning, then move the tractor backward as if you wqere pinning... sort of rocking the tractor fore and aft. While you're doing this, have someone watch the 5th wheel from the side of the vehicle, at the drive wheels. Take note of the movement between the 5th wheel plate and the pickup plate... then take note of any movement between the 5th wheel pivot and the tractor frame... you may want a flashlight.

...do you see any movement?

does it 'bump' when you push/pull on the pin?